Scaladoc: Some implicit classes are too implicit

### Description
Some implicit classes have too many implicit modifiers.
![image](https://user-images.githubusercontent.com/39772805/140059421-d4b8061f-5f9a-42b8-94a4-2c01abc8335a.png)
Location: [Predef](https://dotty.epfl.ch/api/scala/Predef$.html)
### Expectation
Just one implicit modifier